This invention relates to schemes for connecting flexible circuit based electronic device modules to an interconnect substrate through a socket connection.
The use of flexible printed circuits has become quite widespread because of their low cost, ease of assembly in interconnection systems, and the low volumes that they occupy. A flexible printed circuit (or xe2x80x9cflex circuitxe2x80x9d) typically includes a strip or cable with a plurality of embedded electrically conductive lines. The conductive lines may be formed on a relatively thin base layer of insulative material, such as a polyimide sheet or the like. The conductive lines are covered by an overlying layer of insulative material to form an elongated and relatively flexible circuit structure. Apertures may be formed in one of the insulation layers to expose portions of the conductive lines for electrical connection to other electronic components (e.g., the conductors of a complementary mating connecting device, which may be a second flat flexible circuit, a printed circuit board or the terminals of a mating connector). A zero insertion force (ZIF) connector typically provides an electrical interface between the flexible printed circuit and a printed circuit board.
Electronic components may be mounted on flexible printed circuits that, in turn, may be incorporated into electronic device modules, such as charged coupled device (CCD) sensors and complementary metal-oxide-semiconductor (CMOS) sensors. In some cases, a flexible printed circuit may be connected to an interconnect substrate (e.g., a printed circuit board) through a multi-layer ceramic dual-in-line (DIP) package (see, e.g., U.S. Pat. Nos. 5,072,084 and 5,311,007). In other cases, a flexible printed circuit may be connected to an interconnect substrate through a zero insertion force connector. For example, U.S. Pat. No. 6,011,294 discloses a charged coupled device packaging in which an image sensor is housed within a ring frame and is mounted on a flexible circuit board that may be connected to a printed circuit board through a standard zero insertion force connector, an anisotropic adhesive, or a traditional solder butt joint.
The invention features socketable flexible circuit based electronic device modules and sockets for electrically and mechanically connecting the electronic device modules to an interconnect substrate. These systems provide inventive ways in which the electronic device modules may be positioned accurately and securely on an interconnect carrier, while allowing the electronic device modules to be replaced easily without having to resort to laborious desoldering and resoldering operations to remove the modules and connect new modules in their place.
In one aspect, the invention features an electronic device module socket that includes a support frame, a retainer, and an electrical connector. The support frame is constructed and arranged to receive the electronic device module. The retainer is constructed and arranged to engage and thereby mechanically hold the electronic device module in place. The electrical connector is constructed and arranged to electrically connect the plurality of elongated flexible circuit board conductors to a corresponding plurality of electrical conductors of the interconnect substrate.
Embodiments in accordance with this aspect of the invention may include one or more of the following features.
The electrical connector preferably is constructed and arranged to be biased against the plurality of elongated flexible circuit board conductors when the electronic device module is mechanically held in place by the retainer. The electrical connector may comprise a plurality of electrically conductive spring fingers or an elastomeric anisotropic electrically conductive film.
The retainer preferably has a latch portion that is configured to yield during insertion of the electronic device module into the socket and to snap back over an edge of the electronic device module when fully inserted into the socket. The support frame and the retainer may be incorporated within a unitary structure.
In another aspect, the invention features a socketable electronic device module that includes a housing, one or more electronic components, and a flexible circuit board. The housing is constructed and arranged to be inserted within an electronic device module socket for electrical and mechanical connection to an interconnect substrate. The flexible circuit board comprises a flexible substrate having a component portion supporting the one or more electronic components and a contact portion supporting a plurality of elongated electrical conductors and coupled to the component portion through a curved portion. The component portion of the flexible substrate is disposed within the housing and the contact portion of the flexible substrate is disposed outside of the housing and is exposed for electrical contact with an electrical connector of the electronic device module socket.
Embodiments in accordance with this aspect of the invention may include one or more of the following features.
In some embodiments, the one or more electronic components may be supported on one surface of the flexible substrate and at least a portion of the electrical conductors may be supported on an opposite surface of the flexible is substrate. In these embodiments, the contact portion of the flexible substrate may be substantially orthogonal to the component portion of the flexible substrate.
In other embodiments, the one or more electronic components and the electrical conductors are supported on the same surface of the flexible substrate. In these embodiments, the contact portion of the flexible substrate may be substantially parallel to the component portion of the flexible substrate, and the flexible substrate may be folded at the curved portion.
In another aspect, the invention features a socket-based system for electrically and mechanically connecting an interconnect substrate and an electronic device module.
Other features and advantages of the invention will become apparent from the following description, including the drawings and the claims.